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標題: | 台灣地區巨積混凝土配比之早期溫度場模擬與分析 Simulation and Analysis of Early Temperature Field of Mass Concrete Mix Design in Taiwan |
作者: | Shen-Kai Lin 林聖凱 |
指導教授: | 詹穎雯(Yin-Wen Chan) |
關鍵字: | 巨積混凝土,有限元素分析,成熟度法,水化度,台灣巨積混凝土配比,ANSYS, mass concrete,finite element analysis,maturity method,degree of hydration,concrete design in Taiwan,ANSYS, |
出版年 : | 2019 |
學位: | 碩士 |
摘要: | 本文使用 ANSYS 建立了一套以有限元素法模擬巨積混凝土早齡期溫度場的方法。由於國內既往之巨積混凝土工程往往忽略最高心溫與心表溫差對巨積混凝土構件於養護初期以及長齡期下的劣化影響,或是常以分層施工等方式避免溫度裂縫的產生,但卻衍伸出更多力學性質改變的問題,因此應該回歸至巨積混凝土的配比上重新檢討,從降低配比的水化熱出發,始可有效解決巨積混凝土可能產生之問題。
透過絕熱溫升試驗結果來預測混凝土早期水化反應速率,並以成熟度法推導出可同時考慮齡期及溫度效應之混凝土單位體積生熱率,將其設定為模型中的可隨齡期及溫度修正的熱荷載,另外由於巨積混凝土構件內各部分水化程度並不均勻,所以將混凝土的熱傳性質設定為水化度的函數,在每一步階重新計算水化度,以得到更接近真實混凝土水化反應的模型。 以長寬高為 4m×3m×3m 之實尺寸現地試體作為模擬對象,比對模擬結果與監測結果後,確認模型的正確性,再代入透過試驗及計算得到台灣常見巨積混凝土配比之參數進行模擬與分析,建立一個可供工程師設計巨積混凝土配比的參考資料表。 In this paper, ANSYS is used to establish a method for simulating the early age temperature field of the mass concrete by finite element method. Due to the fact that the previous mass concrete projects in Taiwan usually ignore the deterioration effect of the maximum center temperature and the center-surface temperature difference on the mass concrete members during early-curing age and long-term period, they often avoid the occurrence of temperature cracks by layering construction, etc. However, there are more problems in the change of mechanical properties. Therefore, it should be re-examined to the concrete design. Starting from the reduction of hydration heat of the concrete design, it can effectively solve the issues that may occur in the mass concrete. The early hydration reaction rate of concrete is predicted by the adiabatic temperature rise test results, and the heat generation rate of the concrete is derived by the maturity method which can simultaneously consider the age and temperature effect, which is set as age-and-temperature-corrected thermal load in the model. Besides, the hydration degree of each part of the mass concrete members is not uniform, so all the thermal properties of the concrete are set as a function of the degree of hydration, and the degree of hydration will be recalculated at each time step to obtain a model that is closer to the real concrete hydration behavior. The test piece with the size of 4m×3m×3m is used as the simulation object. After comparing the simulation and measurement results, the correctness of the model is confirmed, and then the parameters of the common concrete designs in Taiwan obtained through the tests and calculations will be input to the model for the simulation and analysis. Therefore, a reference sheet for engineers to design mass concrete will be established. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/74110 |
DOI: | 10.6342/NTU201903024 |
全文授權: | 有償授權 |
顯示於系所單位: | 土木工程學系 |
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